import THREE from '../third_party/three.js';

function MeshLine() {

  this.positions = [];

  this.previous = [];
  this.next = [];
  this.side = [];
  this.width = [];
  this.indices_array = [];
  this.uvs = [];
  this.counters = [];
  this.geometry = new THREE.BufferGeometry();

  this.widthCallback = null;

}

MeshLine.prototype.setGeometry = function(g, c) {

  this.widthCallback = c;

  this.positions = [];
  this.counters = [];

  if (g instanceof THREE.Geometry) {
    for (var j = 0; j < g.vertices.length; j++) {
      var v = g.vertices[j];
      var c = j / g.vertices.length;
      this.positions.push(v.x, v.y, v.z);
      this.positions.push(v.x, v.y, v.z);
      this.counters.push(c);
      this.counters.push(c);
    }
  }

  if (g instanceof THREE.BufferGeometry) {
    // read attribute positions ?
  }

  if (g instanceof Float32Array || g instanceof Array) {
    for (var j = 0; j < g.length; j += 3) {
      var c = j / g.length;
      this.positions.push(g[j], g[j + 1], g[j + 2]);
      this.positions.push(g[j], g[j + 1], g[j + 2]);
      this.counters.push(c);
      this.counters.push(c);
    }
  }

  this.process();

}

MeshLine.prototype.compareV3 = function(a, b) {

  var aa = a * 6;
  var ab = b * 6;
  return (this.positions[aa] === this.positions[ab]) && (this.positions[aa + 1] === this.positions[ab + 1]) && (
    this.positions[aa + 2] === this.positions[ab + 2]);

}

MeshLine.prototype.copyV3 = function(a) {

  var aa = a * 6;
  return [this.positions[aa], this.positions[aa + 1], this.positions[aa + 2]];

}

MeshLine.prototype.process = function() {

  var l = this.positions.length / 6;

  this.previous = [];
  this.next = [];
  this.side = [];
  this.width = [];
  this.indices_array = [];
  this.uvs = [];

  for (var j = 0; j < l; j++) {
    this.side.push(1);
    this.side.push(-1);
  }

  var w;
  for (var j = 0; j < l; j++) {
    if (this.widthCallback) w = this.widthCallback(j / (l - 1));
    else w = 1;
    this.width.push(w);
    this.width.push(w);
  }

  for (var j = 0; j < l; j++) {
    this.uvs.push(j / (l - 1), 0);
    this.uvs.push(j / (l - 1), 1);
  }

  var v;

  if (this.compareV3(0, l - 1)) {
    v = this.copyV3(l - 2);
  } else {
    v = this.copyV3(0);
  }
  this.previous.push(v[0], v[1], v[2]);
  this.previous.push(v[0], v[1], v[2]);
  for (var j = 0; j < l - 1; j++) {
    v = this.copyV3(j);
    this.previous.push(v[0], v[1], v[2]);
    this.previous.push(v[0], v[1], v[2]);
  }

  for (var j = 1; j < l; j++) {
    v = this.copyV3(j);
    this.next.push(v[0], v[1], v[2]);
    this.next.push(v[0], v[1], v[2]);
  }

  if (this.compareV3(l - 1, 0)) {
    v = this.copyV3(1);
  } else {
    v = this.copyV3(l - 1);
  }
  this.next.push(v[0], v[1], v[2]);
  this.next.push(v[0], v[1], v[2]);

  for (var j = 0; j < l - 1; j++) {
    var n = j * 2;
    this.indices_array.push(n, n + 1, n + 2);
    this.indices_array.push(n + 2, n + 1, n + 3);
  }

  if (!this.attributes) {
    this.attributes = {
      position: new THREE.BufferAttribute(new Float32Array(this.positions), 3),
      previous: new THREE.BufferAttribute(new Float32Array(this.previous), 3),
      next: new THREE.BufferAttribute(new Float32Array(this.next), 3),
      side: new THREE.BufferAttribute(new Float32Array(this.side), 1),
      width: new THREE.BufferAttribute(new Float32Array(this.width), 1),
      uv: new THREE.BufferAttribute(new Float32Array(this.uvs), 2),
      index: new THREE.BufferAttribute(new Uint16Array(this.indices_array), 1),
      counters: new THREE.BufferAttribute(new Float32Array(this.counters), 1)
    }
  } else {
    this.attributes.position.copyArray(new Float32Array(this.positions));
    this.attributes.position.needsUpdate = true;
    this.attributes.previous.copyArray(new Float32Array(this.previous));
    this.attributes.previous.needsUpdate = true;
    this.attributes.next.copyArray(new Float32Array(this.next));
    this.attributes.next.needsUpdate = true;
    this.attributes.side.copyArray(new Float32Array(this.side));
    this.attributes.side.needsUpdate = true;
    this.attributes.width.copyArray(new Float32Array(this.width));
    this.attributes.width.needsUpdate = true;
    this.attributes.uv.copyArray(new Float32Array(this.uvs));
    this.attributes.uv.needsUpdate = true;
    this.attributes.index.copyArray(new Uint16Array(this.indices_array));
    this.attributes.index.needsUpdate = true;
  }

  this.geometry.addAttribute('position', this.attributes.position);
  this.geometry.addAttribute('previous', this.attributes.previous);
  this.geometry.addAttribute('next', this.attributes.next);
  this.geometry.addAttribute('side', this.attributes.side);
  this.geometry.addAttribute('width', this.attributes.width);
  this.geometry.addAttribute('uv', this.attributes.uv);
  this.geometry.addAttribute('counters', this.attributes.counters);

  this.geometry.setIndex(this.attributes.index);

}

function memcpy(src, srcOffset, dst, dstOffset, length) {
  var i

  src = src.subarray || src.slice ? src : src.buffer
  dst = dst.subarray || dst.slice ? dst : dst.buffer

  src = srcOffset ? src.subarray ?
    src.subarray(srcOffset, length && srcOffset + length) :
    src.slice(srcOffset, length && srcOffset + length) : src

  if (dst.set) {
    dst.set(src, dstOffset)
  } else {
    for (i = 0; i < src.length; i++) {
      dst[i + dstOffset] = src[i]
    }
  }

  return dst
}

/**
 * Fast method to advance the line by one position.  The oldest position is removed.
 * @param position
 */
MeshLine.prototype.advance = function(position) {

  var positions = this.attributes.position.array;
  var previous = this.attributes.previous.array;
  var next = this.attributes.next.array;
  var l = positions.length;

  // PREVIOUS
  memcpy(positions, 0, previous, 0, l);

  // POSITIONS
  memcpy(positions, 6, positions, 0, l - 6);

  positions[l - 6] = position.x;
  positions[l - 5] = position.y;
  positions[l - 4] = position.z;
  positions[l - 3] = position.x;
  positions[l - 2] = position.y;
  positions[l - 1] = position.z;

  // NEXT
  memcpy(positions, 6, next, 0, l - 6);

  next[l - 6] = position.x;
  next[l - 5] = position.y;
  next[l - 4] = position.z;
  next[l - 3] = position.x;
  next[l - 2] = position.y;
  next[l - 1] = position.z;

  this.attributes.position.needsUpdate = true;
  this.attributes.previous.needsUpdate = true;
  this.attributes.next.needsUpdate = true;

};

function MeshLineMaterial(parameters) {

  var vertexShaderSource = [
    'precision highp float;',
    '',
    'attribute vec3 position;',
    'attribute vec3 previous;',
    'attribute vec3 next;',
    'attribute float side;',
    'attribute float width;',
    'attribute vec2 uv;',
    'attribute float counters;',
    '',
    'uniform mat4 projectionMatrix;',
    'uniform mat4 modelViewMatrix;',
    'uniform vec2 resolution;',
    'uniform float lineWidth;',
    'uniform vec3 color;',
    'uniform float opacity;',
    'uniform float near;',
    'uniform float far;',
    'uniform float sizeAttenuation;',
    '',
    'varying vec2 vUV;',
    'varying vec4 vColor;',
    'varying float vCounters;',
    '',
    'vec2 fix( vec4 i, float aspect ) {',
    '',
    '    vec2 res = i.xy / i.w;',
    '    res.x *= aspect;',
    '    vCounters = counters;',
    '    return res;',
    '',
    '}',
    '',
    'void main() {',
    '',
    '    float aspect = resolution.x / resolution.y;',
    '  float pixelWidthRatio = 1. / (resolution.x * projectionMatrix[0][0]);',
    '',
    '    vColor = vec4( color, opacity );',
    '    vUV = uv;',
    '',
    '    mat4 m = projectionMatrix * modelViewMatrix;',
    '    vec4 finalPosition = m * vec4( position, 1.0 );',
    '    vec4 prevPos = m * vec4( previous, 1.0 );',
    '    vec4 nextPos = m * vec4( next, 1.0 );',
    '',
    '    vec2 currentP = fix( finalPosition, aspect );',
    '    vec2 prevP = fix( prevPos, aspect );',
    '    vec2 nextP = fix( nextPos, aspect );',
    '',
    '  float pixelWidth = finalPosition.w * pixelWidthRatio;',
    '    float w = 1.8 * pixelWidth * lineWidth * width;',
    '',
    '    if( sizeAttenuation == 1. ) {',
    '        w = 1.8 * lineWidth * width;',
    '    }',
    '',
    '    vec2 dir;',
    '    if( nextP == currentP ) dir = normalize( currentP - prevP );',
    '    else if( prevP == currentP ) dir = normalize( nextP - currentP );',
    '    else {',
    '        vec2 dir1 = normalize( currentP - prevP );',
    '        vec2 dir2 = normalize( nextP - currentP );',
    '        dir = normalize( dir1 + dir2 );',
    '',
    '        vec2 perp = vec2( -dir1.y, dir1.x );',
    '        vec2 miter = vec2( -dir.y, dir.x );',
    '        //w = clamp( w / dot( miter, perp ), 0., 4. * lineWidth * width );',
    '',
    '    }',
    '',
    '    //vec2 normal = ( cross( vec3( dir, 0. ), vec3( 0., 0., 1. ) ) ).xy;',
    '    vec2 normal = vec2( -dir.y, dir.x );',
    '    normal.x /= aspect;',
    '    normal *= .5 * w;',
    '',
    '    vec4 offset = vec4( normal * side, 0.0, 1.0 );',
    '    finalPosition.xy += offset.xy;',
    '',
    '    gl_Position = finalPosition;',
    '',
    '}'
  ];

  var fragmentShaderSource = [
    `#extension GL_OES_standard_derivatives : enable
    precision mediump float;

    uniform sampler2D map;
    uniform sampler2D alphaMap;
    uniform float useMap;
    uniform float useAlphaMap;
    uniform float useDash;
    uniform vec2 dashArray;
    uniform float dashOffset;
    uniform float visibility;
    uniform float alphaTest;
    uniform vec2 repeat;

    varying vec2 vUV;
    varying vec4 vColor;
    varying float vCounters;

    void main() {
      vec4 c = vColor;
      vec2 tuv = vUV * repeat;
      if(useDash == 1.) {
        tuv.x = mod((tuv.x + dashOffset),1.);
      }
      if( useMap == 1. ) c *= texture2D(map, tuv);
      if( useAlphaMap == 1. ) c.a *= texture2D( alphaMap, tuv ).a;
      if( useDash == 1. ){
        if(mod(vCounters*repeat.x+dashOffset,1.)>(dashArray.x / (dashArray.x+dashArray.y))) {
          c.a = 0.;
        }
      }
      if( c.a < alphaTest ) discard;
      gl_FragColor = c;
      gl_FragColor.a *= step(vCounters,visibility);
    }`
  ];

  function check(v, d) {
    if (v === undefined) return d;
    return v;
  }

  THREE.Material.call(this);

  parameters = parameters || {};

  this.lineWidth = check(parameters.lineWidth, 1);
  this.map = check(parameters.map, null);
  this.useMap = check(parameters.useMap, 0);
  this.alphaMap = check(parameters.alphaMap, null);
  this.useAlphaMap = check(parameters.useAlphaMap, 0);
  this.color = check(parameters.color, new THREE.Color(0xffffff));
  this.opacity = check(parameters.opacity, 1);
  this.resolution = check(parameters.resolution, new THREE.Vector2(1, 1));
  this.sizeAttenuation = check(parameters.sizeAttenuation, 1);
  this.near = check(parameters.near, 1);
  this.far = check(parameters.far, 1);
  this.dashArray = check(parameters.dashArray, new THREE.Vector2(1, 0));
  this.dashRatio = check(parameters.dashRatio, 0);
  this.dashOffset = check(parameters.dashOffset, 0);
  this.useDash = (this.dashArray) ? 1 : 0;
  this.visibility = check(parameters.visibility, 1);
  this.alphaTest = check(parameters.alphaTest, 0);
  this.repeat = check(parameters.repeat, new THREE.Vector2(1, 1));

  var material = new THREE.RawShaderMaterial({
    uniforms: {
      lineWidth: { value: this.lineWidth },
      map: { value: this.map },
      useMap: { value: this.useMap },
      alphaMap: { value: this.alphaMap },
      useAlphaMap: { value: this.useAlphaMap },
      color: { value: this.color },
      opacity: { value: this.opacity },
      resolution: { value: this.resolution },
      sizeAttenuation: { value: this.sizeAttenuation },
      near: { value: this.near },
      far: { value: this.far },
      dashArray: { value: this.dashArray },
      dashOffset: { value: this.dashOffset },
      useDash: { value: this.useDash },
      visibility: { value: this.visibility },
      alphaTest: { value: this.alphaTest },
      repeat: { value: this.repeat }
    },
    vertexShader: vertexShaderSource.join('\r\n'),
    fragmentShader: fragmentShaderSource.join('\r\n')
  });

  delete parameters.lineWidth;
  delete parameters.map;
  delete parameters.useMap;
  delete parameters.alphaMap;
  delete parameters.useAlphaMap;
  delete parameters.color;
  delete parameters.opacity;
  delete parameters.resolution;
  delete parameters.sizeAttenuation;
  delete parameters.near;
  delete parameters.far;
  delete parameters.dashArray;
  delete parameters.dashOffset;
  delete parameters.dashRatio;
  delete parameters.visibility;
  delete parameters.alphaTest;
  delete parameters.repeat;

  material.type = 'MeshLineMaterial';

  material.setValues(parameters);

  return material;

};

MeshLineMaterial.prototype = Object.create(THREE.Material.prototype);
MeshLineMaterial.prototype.constructor = MeshLineMaterial;

MeshLineMaterial.prototype.copy = function(source) {

  THREE.Material.prototype.copy.call(this, source);

  this.lineWidth = source.lineWidth;
  this.map = source.map;
  this.useMap = source.useMap;
  this.alphaMap = source.alphaMap;
  this.useAlphaMap = source.useAlphaMap;
  this.color.copy(source.color);
  this.opacity = source.opacity;
  this.resolution.copy(source.resolution);
  this.sizeAttenuation = source.sizeAttenuation;
  this.near = source.near;
  this.far = source.far;
  this.dashArray = source.dashArray;
  this.dashRatio = source.dashRatio;
  this.dashOffset = source.dashOffset;
  this.useDash = source.useDash;
  this.visibility = source.visibility;
  this.alphaTest = source.alphaTest;
  this.repeat.copy(source.repeat);

  return this;

};

export { MeshLine, MeshLineMaterial };